Energy absorbing mechanisms typically are either mechanical or hydraulic and sometimes a combination of hydraulic and mechanical systems. This invention concerns itself with mechanical energy absorbing means. Mechanical energy absorbing means typically utilize a basic spring mechanism and some sort of friction system to dampen or absorb the force effects caused by the spring. As a general rule, the mechanisms for controlling the spring rate are bulky or large and do not provide an effective control of shock forces in any simple manner. Nearly all of the existing mechanical energy absorbing systems have one or more of the following disadvantages:
--require close manufacturing tolerances; PA1 --are sensitive to extreme temperature changes; PA1 --mechanical types are sensitive to changes in the friction coefficient; PA1 --production of a sharp load spike at the beginning of a stroke due to the initial breakaway friction coefficient; PA1 --sensitivity to stroking velocity; PA1 --fluidic types are subject to leaks;
Fluidic energy absorbing systems also include disadvantages of:
In addition, material deformation types of energy absorbers are limited to one-cycle or one time operations.